What do you get when you cross a couple of scuba tanks and a 1978 Sachs moped? Ideally,
an air-powered two-wheeler to give you a boost up Houghton's hills, backed up by leg
power if the air runs out before you get home.

That's the idea behind an air-driven moped developed as a Senior Design project in
the Department of Mechanical Engineering-Engineering Mechanics. Advisors James De
Clerck, a professor of practice, and graduate student Nick Mastricola lead the five
team members: Adam Bieber, Andrew Bomstad, Jared Recker, Joshua Schmidt and Benjamin
Vindedahl. The moped was exhibited at Tech's Undergraduate Expo.

"It's a hybrid between a moped and a bicycle," says Bomstad. Two standard scuba tanks
containing 3,000 psi of air are mounted on either side of the rear wheel. The driver
can pedal around using the moped's bicycle gears or engage the pressurized air to
reach a top speed of about 12 mph on the flat.

The team wanted to build a moped that never needed to stop at a gas station and could
be powered by a renewable energy source. However, they noted, just being air-powered
doesn't necessarily make it environment-friendly. Powering an air compressor to fill
the tanks takes energy, so the moped is only as green as the compressor's power source.

That said, the air-powered moped has a quality that not even a hydrogen-powered vehicle
can claim: no emissions other than plain old air. Period. "It would be perfect for
getting around in enclosed spaces, like a warehouse," Bomstad says.

While the team members are pleased with their handiwork, they didn't get to build
the moped of their dreams. It can only travel about a mile and a half on air power
alone, much less than they had hoped. The shortfall is due in part to "overly optimistic
estimates of torque requirements" and funding constraints. A little research revealed
that using super-light carbon fiber air tanks and the ideal air motor would push their
budget well over the limit.

That's OK, says De Clerck. "They learned a lot about the design process; they started
with ideal goals and had to compromise," he says. "And they did a great job of applying
mechanical engineering concepts. This was a very good approximation of a real-world
experience."

Michigan Technological University is a public research university, home to more than
7,000 students from 54 countries. Founded in 1885, the University offers more than
120 undergraduate and graduate degree programs in science and technology, engineering,
forestry, business and economics, health professions, humanities, mathematics, and
social sciences. Our campus in Michigan’s Upper Peninsula overlooks the Keweenaw Waterway
and is just a few miles from Lake Superior.